Sighting instrument



Nov. 23, 1943.

J. T, ZAK SIGHTING INSTRUMENT Filed Se t. 2, 1942 4 Sheets-Sheet 1 gwwm \JnaE h '1 211K Nov. 23, 1943. .1. T. ZAK

SIGHTING INSTRUMENT Filed Sept. 2, 1942 4 Sheets-Sheet 2 Joseph T. 215K Nov. 23, 1943. T AK 2,334,739

S IQHIING INSTRUMENT F iled Sept. 2, 1942 4 Sheets-Sheet 3 Wop J. T. ZAK

SIGHTING INSTRUMENT Filqd Sept. 2, 1942 Nov. 23, 1943 4 Sheets-Sheet 4 awe/whoa TJcIeE I-L '1" ZnK Patented Nov. r i

2 1573 .j SIGHTING INSTRUMENT...

. a e i? ee T AnlflicationSeutemher2,194258e1 ia1No.456-,980

Q12 c aims.

(Gu'anted u1.1dk,$r the act ,of March 3.1883; as

amended April 39, 1 5128; 37-0-0. GU15?) The intention describdjherein may be manu factured and used by or for the Government for governmental purposes, Without the paymentfto me of any royalty thereon;

/ 'I'his invention relates to aninstrument adapted to be used for range measurement, horizontalangle measurement, angle of site measurement,

and/or magnetic azimuth measurement. V

This invention to a certain extent relates to an improvementin the instrument of the type; disclosed in my U'. S. Patent2,08,722 issued July 28, 1936; a magneticazimuth finder is inc'ore porated in the instrument and the improvements areof such a nature as to make this instrument closely approach-the effectiveness of precision instruments with lenses. e i

An object of this invention is to providefan instrument of the above character which is adapted to be eas ly and q y op rat to any p s o o determ n n the r n rizonta angle, angle of site and magnetic azimuth to meet the conditions of direct and indirect laying overhead fire) withla machine gun orth'e like. J Another object of this invention is to proyide a range finding, horizontal angle measuring, magstrument which is simple in construction, eflicient in use, light in weight, and-which'isnot apt to getcut of order.

The specific nature ofthe .inventionas well as other objects and. adyantages thereof w ill'clearly appear from a descriptionof a preferred embodia ment as shown in the accompanyingdrawings in which:

Fig. 1 discloses'an instrument assembled i011 range finding and horizontal angle measure'- ments. v

Fig. .2 discloses the angle of site readings. v

Fig. 3 is helpful in explaining the manner in which a range reading is obtained.

Fi 4 d oses t ame instrumen o Fig. i rea m l an ha n m n -there n to; 9 2-:

tamin ma eti azimuths.

Fi s. 5, a. '1 n 8 are .m s ifiedar ah merits forclamping arms AIB; C of the instrument in Fig. 1. In. addition, Fig"? discloses steadying means on arm C.

trume t q'f F 1 .ar heemhloyed as al s tra tor Lin coniunctiohwith ma s or dr in V Fig. 11 discloses the manner' in whichthe-in '25 netic a u h measurin an ah e fsiteinsame instrument reassembled and havingmeans thereon for Obtaining h in which h i fmine one of the three quantities, angle m rg ran e. vert a di tance any We the quant ie arehhe he inst ument o e ice 9n. th .1. {0f F nd Fi s 13 5. e ecti lyt is vlqsesa s a u when in rumen o he F 1 e use ah allele o sit strument.

h ss .1? dis les mod fi d com ines range findin a an le at s te meas ing ins rument 1n. W b iti ob ious that .the' materia ma he ub titut d f 1 It s a pa e wrqm i .1 at the a m A B. c a wi l pain ansu h adju tment w h one an tlhfirjahl arms Aaiid. 3 wil he ate constant d tan e mxh he ope ato s nos g n Port on 'A IP JAJ B c ar hel iihi naca el tion hi o on n by "means of jbolt thaving wing nut or similar clamping means I thereon. Bolt Z-is pivotably mounted on arm (-3 by means' of a pin which passes through a hole intl'leend of bolt 2 and which is "frictiqnallyhld in'thearm Slot 4 in the forward end of armG is made-large enough so as to allow at least a'ninetydegree pivotal mover.

'ment of arm (3 when wing nut l is released whereby the instrum'entmay in its carrying positionwbe compactly folded to a substantially rectangular block having alength 1 substantially equal to the length of one of the armsanda thickness wh h is substantially three times the thickness Qf 99. 40 of-thearms; I f r i i i Range finding.

The method. employed in determining the range to a target is similar to that described in my 1 above mentioned Patent 2,048,722; issued July 28, 1936. Reference will .behad to theggraphic representation in Fig. 3 wherein the; line '19? represents a fixed :know-n distaimfl the base line.- Atpositionsfl. the 9%?! Flag? I notch IO' against the ridge ofhi sn with his lefthand supportingithe instrumen hand free. mhe observer alignsth c of mark-5.9m the ri ht hand .1 51 49, a, projecting peg or lnai nfi I taining this alignment he an man:

' ri -T 12 and 4; dis hs a meet seam h stens;

- the target.

object such as a tree and slides thefadjustable a slide 'liwith his right handuntilmark E6 on slide l coincides with the tree. Thus an indication of angle Tlltree is obtained from readings, a, b..on..respective arms A, B of the instrument. A known distanceis stepped out alongthe line 0-tree to pointll which defines the end'of' the 'base. line. The operator then. repeats the eye and all sighting. over line it on B is accomplished with the left eye. Also, it'is noted that if the reference mark and. target are transsimilarly obtained by laying line2t on the reference obje'ctrand'sliding mark Iii .to coincide with- A varnis hed linen stringprovides a good means for determining the base line distance liil'jbut, if an assistant is present the instrument itseli" may; by changing it to "an angle of sightinstrument ina' manner to be'described below; be usedfor that purpose. lnthat' case the observer directsfthe assistant at ilto face in the direction; of 0 and to have extended in hisoutstretched arn'ls 'a string of computed length. The observer who is onthe'lin'e extending from it to the reference point and in'the vicinity of notes the angle in mils subtended bythe st ing which is heldat ti and hence may determine the exactdistanc'efrom ii tothepoint'fl. Where he" made the angle oi sight'measurements. A correction will have tofbe applied to the angular readings obtainedoh, scale" Ii in an amount determined by the deviation, of the exact distance it froma pre'determinedv distancewhichwas the basis for lfi and th e cor esponding mil or distance (as in this instance). correction at lit. These corrections may'be obtained by using the following;

formula: RMzequals 1000W.where R is therange,

Mth ngula width in rnilslof the targetoribase line,- and'W thelinealwidth oi the targetbr base line." For .the sake offaccuracy the base. line length should be. made. longeras, the range to be measured is increased.1.-'. V It is apparentithat" scales similar I to the .ones

- Reading horizontal angles V 'The observer places. notch .1 ll on'the ridge of thecalibrationofscale l t. These corrections in percent maybe conveniently placed on'arm A at Reading angles ofsite In order to read angles of site the arms A, B, C are arranged as in-Figure 2. and a level 21 and its housing 27a which hing'edly carries mirror 28 is bolted to arm C by means of auxiliary common a clamping bolt passing through auxiliary hole ii inmember C.

The observer in this a 7 reference point and at the same time moves the instrumenthntil the bubble in the conventional spiritlevel 2? stands in its level position; the observer then tiltshis head slightly maintaining the bubble in-levelposition anddeterniines where f his line of vision to the distant target intersects the' scale 28. The point of intersection of course ives an' indication of the an ular elevation of I posed an indication of the above angles'may be; g 1 g L the target. I

During :the above' sightin gjoperations sthe end. i r'm A est'sfon"theiobservefs cheek below and 'netic' compass needle 33 has housing 31 deviation of "the observer target line fro'm"-the{ 1 magnetic north position maybe determineddiclamped to'arm Cby mean's o'f th'umb screw '33 and bolt 32 whioh is e'arried "by" housing 3"! and which extends through auxiliary hole r (Fig-. 1):

inarr'n C; also auxiliary thumb screW 30 on auxiliary bolt 31 whichpasse's through auxiliary hole 9 (Fig. 1) serves to 'clampanris A and-Ctogether;

','Compass'housing fii'carriesth bridge member 35 having a centrally disposejdvvire '36 which is aligned with the zero mark" B in the above assembly;

The observer'resting the cheek under his' right" eye on the end of arm Asights along the instrument and aligns the slit to in mirrored member 39"With wire 35, at the saine'time moving the instrument until the mirroi image of the south pole end "of .the'magne't isfq llidistant' between ab'utments eh- 5 l a The target and notes the intersection of-hisline of That scalejmay be calibratediin lmil's so that the rectly;

Fig. 5 B, C in Fig. lmay be'clamped together.

discloses another wayin which arms A,

C and projects throughholes in arm B, C in Fig. l may'be"'clamped-togeth'erf Inthis' instance the arm C has'fa rectangular cuteout porhis nose and between'his .eyes; he supports the v instrument and moves the slide 15 .as in the above range-finding operation-.gDuring every reading the instrument must. beheldxat such an angle 'With the head th'at'the rightey'e. will always tion which receives the "ends of arms A" and B in such a manner that contiguous surfaces of the armsfaref flush with one another. 1 Clamping bolt 2b" is .anc'hored in arm c; and projectsthrough holes in A and B and carries clamping nut lb; If so desired, the. arms A and B,.jmay.be"se- V cured'in-the end'of arm Cby a. fullinoi tise wig.

6a). by means ofscrew 2b and nut 'll instead ,Q s -"6.1;.

Fig. 7 discloses a modification orjtne; a range ment shown liig-Q 1, "In. this instance clampin of-in a groove inlth'e' end of .l arrangementflines up a mark-2!) on the level-housing 21a with the zero sighting procedureoutlined above'whe'reby an inmark of scale 28 on arm B and with dlstant dication as .to angle 'I?0 tree is obtained by.

arms A, 3,0 are arrangedas in FighreAahdj-a magof scale" 5% cam-m rear side-ofsi'ghting member 39' isniir'rored and placed at *such 7 an angle that the observer from his sighting position readily sees the. south end of thejmaghet. When" I the above'posltion of the instrument/is obtained the observer then with the same eye sights on-the- Q In this instance bolt Zafis fixedly mounted'in-the endof assigns bolt ic anchored in arm Apasses througha hole in arm B, and through projectioncrjonarm C with one another and a clamping bolt 2d anchored in arm C carrying clamping nut Id serves to hold the arms A, B, Ctogeth'er. l

Figg9-discloses a steadying'device Bil mounted on the arm Qforuse during range determinations. The steadying device Gil has a right angle cut-out portion adapted to have inserted therein one of the right angles ofarm C. A clamping bolt l passing 'through'liole 8(Fig. l) 'inarmG and vhole 60a in "the steadying device carries clamping nut H. The curved end-"Gilli of-the 'stea'dying device ispressed against the observers forehead above his right eye while notch H) rests on the ridge of his nose thereby preventing slippage. With this steadying device 60 in place on the arrangement shown in Fig. lithe aligning marks 5, (Fig.1) arefou'nd unnecessary because the steadying device Bil serves to keep the arm- C at a constant angle with the observers eye.

Fig. 10 discloses the manner in which arms A and C of the arrangement shown in Fig. 1 may be used to measure angles or as a protractor. The arm C and arm A which has the mil scale I I thereon is arrangedas in Fig. '10. with the mil scale facing inwardly. A common straight pin is inserted through pin hole 8i] in arm 0 and through the reference point Z on the map or drawing under consideration; Pencil rays are drawn through points X, Y on the map and through point 2. Angular distances are read on the mil scale directly; ,in this instance, the angle subtendedis'300 mils.

Fig. 11 discloses the manner in which the vertical interval or vertical distance of a distant object may be determined knowing its range and the angle subtended thereby. Thi particular ar rangementdisjclosed inthis figure servestoteach the manner in which the length of the base line 0-6 in Fig. 1 may be determined when as recited under Range finding an assistant holds a known length of string. 'The arms A, B, C of Fig. 1 are arranged as shown in Fig. 11. The arm B is not attached to arm A or. arm C but is movable by the operator. A string S is tacked at the zero point of the range scale on arm Cand drawn taut by the observer's hand so as to intercept the mil scale on arm A at a known crunknown value. The zero mark of the vertical interval scale (in lineal dimensions) on arm B is made to coincide with the known or unknown range and the intersectionof, the string S with scale on arm B will determine the corresponding vertical interval. It is. obvious from principles of geometry that knowing any two of the three quantities. range, subtended angular distance, orvertical interval of the distant object, the remaining third quantity may be determined by the means disclosed in conjunction with Fig. 11. i

Fig. 12 discloses another steadying device which may be place-don th instrument of'Fig. 1'; Figure 13 discloses thesteadying device of Fig. 12 in an angle of sight measuring arrangement. The steadying brace I00 is clamped in the groove IBI (Fig. 13) in arm C in range finding and hori- "zontal anglemeasuring arrangements; The end -I"0Ila-of-brace IOIl is braced on the observer's face above hisleft eye and'n'ot'ch H) restson the ridge of his nose. In the angled sight arrangement in Fig-13 the brace I08 is mountedonarm A with clamping bolt I02 passing through hole I53 (Fig. 13) in, the brace I00 and through hole I64 arm A. The instrument'in Fig. 13 is aligned by aligning zero mark I05 on the end of arm A with the zero market the angle of sight scale onbrace I00 and simultaneously bodily moving the instrument until the bubble in spirit level E03 stands in level position. Theobserver then sights cnthe distant target and" notes the' 'point on scale IIl'l where his'line of vision intersects the angle oi sightscale; 1 It is noted that in the arrangement in Fig. 13-no mirror is necessary to see the bubble in spiritlevel I06. v

In this particular arrangement the brace I00 has the angle of sight scale thereon andif de sired the slide I5 of Fig. 1 could have an angle of sight scale thereon so as to serve the same purpose of brace lilll in Fig. 13. This will be more apparent later.

Fig. 14 discloses another steadying device which may be placed on the instrument of Fig. l and Figll15 discloses said steadying device in an angle of sight measuring arrangement. The steadying device I03 is clamped to arm C at an angle of approximately forty-five degrees with the axis of arm 0 by means of the bolt I69 passing through the steadying device holle HQ "and hole III in arm C. The steadying device has a V notch H2 for sighting purposes which separates thebrace surfaces H3 and H4 on the steadying device.

Surface H3 is adaptedto rest on the observers provide three steadylng points on the instrument.

a Fig. 15 discloses the apparatus of Fig. 14 ar-v ranged to measure angle of sight. Arm A is clamped to arm C by means of clamp bolt H5 passing throughholes' in arms A andC. The instrument is aligned by aligning zero marl: I it on steadying device I08 with the zero mark of scale I I! on arm B and simultaneously moving the instrument until the bubble in spirit level I it is in the levelposition. Mirror I I9 on steadying mem ber I08 furnishes a means for viewing the bubble in spirit level H8. The observer then sights on the" distant target and notes th intersection of his line of vision with the scale on arm B.

Figs. 16 and 17 disclose a modification charand cheapness of construction.

Fig. 16 discloses the modified instrument ar ranged for range finding and measurement of horizontal angles. The arms A, B and Care clamped together in a similar manner as shown in'Fig. 8 but the bolt id is anchored in arm 0 as the bolt 2a in Fig. 5. A block 520 is fixedly mounted on arm A and has projected thereon the zero mark of mil scale Ii on arm A. Theyslide acterized by its simplicity, ease of manipulation I5 is adjustably mounted onar'm A; also, arm

or peg I2! in arm C serves as a steadying device."

In this arrangement the mil scale 5 I will not'be' visible to the observer when he is sighting and therefore the zero of that scale is projected on block I20.

H are movable is. assem s in E e-,. 7- ..The; -QbSrve aces the cheekbe qw h s. r e te ea a n t erm'B and a isnsze l 12 on block 2 h-the, ze o .ormeanae .Q y gh c le rr-s id 1 a dj ie rnultaneously levels the bubble in spirit level J23 carried on arm C, He then'sightson the distant target and notes theintersection of his n c i n w th therscale v 4 qnithe l de '51 The slide it is clampedtoarmA by means of thumb. sc ew lid on an a so ia ed screw: [25, Screw I25 is adaptedto pass through hole I26 (Fist- 6 a unders o d t at are ease en shown: in the drawings, only these scales are shown Which aid in, explaining the-,0perationof theinstrument under discussion and it is understood that the actual number of scales whieh may be placed onthe various members may and aremore than those shown in anyone particular figure; usually only one scale per figureis shown inorder to avoid confusion'in thernind of the re de l e r .I mz. ..;v

1. A range finding, horizontal angle -.measur-' ing, and angle of site instrument comprising a I trio of arm members pivotally connected ,to-

gether, one of said arm members providing means for holding the other of said arms a predetermined distance from the: free end tnereof, said freeendhaving a slot therein, a bolt pivotally mounted in the slot the remainingarms of said trio being pivoted on ,said bolt, and clamping means 'on the free en dIo f the bolt whereby said remaining arms may be. clamped with their longitudinalaxes perpendicular tothe axis of saidfirst'membcr orparallel'to the; axis cf said first member.

' A rangefinding horizontal angle rheasur ing and angle of site instrument comprisingat least two arms connected together, oneof said arms having a V notch adapted to receive the angleo f-site scale thereon and being adapted to be disposed on the instrument in angle-orsite reading relation.

3. A range finding, horizontal anglefmeasurf ingfand'angle of site instrument comprising at least a pair oi arms connected together, one. of said arm members having a V notch adapted to receive the bridge of the observer's nose a steadying brace mounted on the last mentioned arm and having a V notch therein separating two surfaces on the brace which are adapted to engage points on the observers face, and. said last mentioned V notch providing a sight.

l. The same as in claim 3 and said last mentioned arm having a spirit level thereon, said steadying brace beingmounted with its axis at an angle of substantially forty-dive degrees 'tothe last mentioned arm, and a mirror on the steadying brace. I

. 5/A'range finding, horizontal angle measur-v ing and angle of site instrument comprising at least two arm members, one of said members providing means for holding the other arm member .a-predetcrmined distance from the free end of said holding member, a sighting member having aiming marks slidably mounted on said other member, an angle of site scale on the si h in memb n y een f r t n th e.h f mem e n "t s um nt ma a e site measuring relationship.

6. A rage finding horizontal 1 angle Incas uring and angle of site instrument comprising 'at' I leasttwo arms connected together, one of said arm members having a Vnotch adapted to receive the bridge of an observers nose, and a steadying brace adjacent said notch comprising two oppositely disposed members adapted tci rest upon; the cheeks and forehead between'fthe ob serversieyes.

7. A range finding horizontal angle measuringand angle of site instrument comprising at leasttwo armsconnected together, one of said arm membershaving a] V notch adapted to receive the bridge of an observers nose,'-and a steadying brace releasably mounted on the last menti ned arm and having a projection adapted to engage the observers forehead. y l

. 8.-A range findinghorizontal angle measuring and angle of siteinstrument comprising at least two ,arms connected together, one of said arms having a V notch adapted to receive the bridge of anobservefs nose,.a steadying brace mounted on thelast mentioned arm and adapted to. en-' gage at least one point on the observers" face, said steadying brace having an angle of site scale thereon and being adapted to be disposed on the' instrument inangle of sitereading relationship, and a spirit level mounted on said last mentioned arm and in close proximity to the V notch. 9. A range finding, horizontal angle measuring and angle of site instrumentcomprising at lea-st two arm members, one of said members providingrneans for holding the other arm member a predetermined distance from the free end of said holding member, a sighting member having aiming marks slidably mounted on said other arm member, an angle of site scale on the sighting member, means 'for mounting the sighting meniberon the instrument in angle of site measuring. relationship, and a spirit level mounted on free end of said member. v

10, An angle of site instrument comprising a. substantiallyT-shaped instrument, the horizontal portion of said T having an angle of site scale thereon, a spirit level mounted on the vertical portion of said T,'a'inirror mounted onfthe, instrument forreflecting the optical image of the spirit level bubble, and the'iree end of the er-- .tical portion of the T being adapted to contact anobservers facet I I I I 1 I 11, A magnetic azimuth measuring instrument comprising a substantially Tr-shaped instrument, thehorizontal portion of said 'T having a magnetic azimuth scale thereon, a magnetic compass needle mounted on the ,verticalportion of the T, a pair. of abutments on oppositesides of, one endof the needle, a mirror mounted onthei instrument for reflectingtheoptical image of the pair of abutments and said needleend, .the ver-' said 1 JOSEPI-IT. zen; 

